[patch][cla] encryption wrapper for dojox.storage

Description

This patch adds an encryption wrapper on top of dojox.storage at dojox.storage.encrypted. It exposes all the methods that dojox.storage does.
One of the major issues with client side persistent data storage is security. With DNS spoofing attacks you can overcome all domain-based access restrictions. One way to get around this is to encrypt all keys and values in the store.
Software encryption via JS is not a performance kicker, but sometimes security is more important than performance.